What is bigger 9/10 or 7/8

You start by cross multiplying:

9 x 8 = 72

This is considered the fraction on the left's value.

You do the same for the other side:

10 x 7 = 70

This is considered the value of the fraction 7/8

72 has a greater value than 70.

Therefore, 9/10 is larger.

9/10 is 2.86% more than 7/8.